Method of making a reconstituted tobacco sheet having improved filling power



March 4, 1969 w. P. SCHWEITZER ET AL 3,430,634

- METHOD OF MAKING A RECONSTITUTED TOBACCO SHEET HAVING IMPROVED FILLINGPOWER Filed April 14, 19s? li TTORNEYS United States Patent 2 ClaimsABSTRACT OF THE DISCLOSURE A reconstituted tobacco sheet is formed, andwhile the sheet is wet and being carried by a rotating support roll, itis doctored off the roll to produce a crepe in the sheet. The dried,creped sheet may then be cut up to produce a filler material forcigarettes or cigars.

This invention relates to a process for making an improved reconstitutedtobacco sheet.

The utility of any particular reconstituted tobacco depends to aconsiderable degree upon the extent to which shreds or pieces of thereconstituted tobacco sheet fill out a cigarette or cigar firmly. Thisability to firmly fill out a cigarette or cigar is referred to as thefilling power of the tobacco. Conventional reconstituted tobacco hasmuch better filling power than the stems or fine fragments of naturaltobacco from which it is often made, but its filling power may beinferior to some types of natural leaf tobacco. To achieve anyparticular amount of cigarette or cigar firmness, it is obvious thattobacco having improved filling power will enable the manufacturer touse less tobacco. Hence, a tobacco product having increased fillingpower as compared to an otherwise identical product is certainlydesirable.

It is therefore an object of the present invention to provide a methodof making reconstituted tobacco sheet which, when cut up or shredded,has a filling power greater than pieces or shreds of an otherwiseidentical sheet.

As is known, one process for making reconstituted tobacco involvestreating natural tobacco to separate soluble extractibles from thefibrous portion, conversion of the fibers by papermaking techniques intoa paper-like fibrous web, and incorporation in the web of the extract torestore the soluble tobacco ingredients. The present invention involvesan additional step to the procedure outlined above, namely, that ofcreping the reconstituted tobacco sheet.

In a broader sense, the invention involves creping a reconstitutedtobacco sheet regardless of the process by which the sheet was produced.

The accompanying drawing illustrates, schematically, an apparatus forcreping a reconstituted tobacco sheet, the apparatus itself being wellknown.

The first step in carrying out the present invention is the formation ofa reconstituted tobacco sheet. One way of producing such a sheet is toextract the soluble ingredients of natural tobacco, which preferably hasbeen macerated or comminuted in preparation for extraction. Theextraction is performed by use of water, and generally withdraws from25% to 60% by weight of the starting material. An aqueous slurry is thenformed containing the fibers, and by usual papermaking techniques, theslurry is transformed into a self-sustaining web. The tobacco extract isthen introduced into the Web. The application of the extracted tobaccomaterial may be achieved in any appropriate manner, as by spraying,saturating, or otherwise.

Another way of producing a reconstituted tobacco 3,430,634 Patented Mar.4, 1969 sheet involves pulverizing natural tobacco and forming anaqueous slurry including the pulverized tobacco and a binder. The slurryis extruded onto a moving belt, whereon it takes the form of atobacco-carrying film.

Still another manner of making a reconstituted tobacco sheet is similarto the first method described above, except that no extraction isperformed. Thus, natural tobacco is formed into an aqueous slurry, andthe slurry is transformed into a web by papermaking techniques. In sucha procedure, the liquid portion of the slurry is saved and reused sothat the soluble portion of the tobacco is not lost.

According to the present invention, after the reconstituted tobacco webis formed it is creped. The creping can be accomplished by pressing theweb, while moist, against a support roll 10. The web 11 is advanced, inthe direction of the arrow in the drawing, onto the periphery of theroll 10, which rotates in the direction of the arrow. The moist web ispressed against the surface of the support roll 10 such as by a pressureroll 12. As the support roll 10 continues to rotate, the still moistsheet 11 is creped off the roll 10 by a creping doctor 13, as a resultof which the sheet takes on a wavy shape, as indicated at 14. When thecreped, reconstituted tobacco sheet thereafter dries to its normalmoisture level, the Wavy shape becomes set in the sheet. If desired, asecond doctor 15 may be provided to clean the roll 10.

A conveyer 16 may be provided for receiving the creped tobacco productas it leaves the support roll 10, and for carrying the tobacco productto a suitable apparatus in which it is dried. Thereafter, thereconstituted tobacco sheet may be cut to provide filler material for asmokable article, e.g., shredded to form cigarette filler material.Shreds of the dried, creped reconstituted tobacco sheet have been foundto possess greater filling power than shreds of an uncrepedreconstituted tobacco sheet.

If the first method described above is employed to make the web ofreconstituted tobacco, the web is creped between the time it isimpregnated with the extract material and the time it is dried to itsnormal moisture level. In such a case, the roll 10 may be a roll whichsupports the web 11 during the impregnation step, or it may be aseparate roll provided solely for purposes of creping the web. In eithercase, the web will be moist with the tobacco extract at the time it ispressed against roll 10 and then creped off.

Tests on both bulk shredded tobacco and on finished cigarettes have beenmade to indicate the improved filling power of tobacco productsaccording to this invention. The bulk tests were performed by the methoddescribed in the article, Measure of the Filling Optimum ofCigarettes-The R Meter, by Andre Pietrucci, Annales S.E.I.T.A.D.E.E.,Section 1, 1965, No. 3. To practice this method, an instrument defininga chamber of fixed volume is used, the chamber having a flexible bottomwall operatively connected to a mercury monometer. Samples of bulkshredded tobacco are placed in the chamber and, after the tobacco iscompressed to the fixed volume, the pressure which each sample exerts onthe flexible bottom of the chamber is read on the monometer. Bycomparison with tobacco from manufactured cigarettes, it can bedetermined that a certain pressure reading corresponds to the firmnessof a satisfactory cigarette. A series of pressure readings is made ineach of which a different weight of tobacco is placed in the chamber.Then, from this information, the weight of tobacco producing a pressurecorresponding to the previously determined standard is found.

The cigarette tests were performed by making cigarettes with differentweights of creped tobacco and different weights of otherwise identicaluncreped tobacco,

and subjecting the cigarettes to a compressibility tester to indicatetheir relative firmness. This tester includes a rounded, weightedplunger, the shape and weight of which is intended to simulate pinchingof the cigarette with the fingers. The depth of depression of theplunger into each cigarette is measured in millimeters, and therefore,comparison of the readings is an indication of the relative firmness ofany cigarette.

Specific examples of the tests are set forth below.

EXAMPLE I A reconstituted tobacco sheet was manufactured, by the firstmethod described above. A length of the sheet was obtained withoutcreping for use as a control. Another length of the sheet was creped,the creping serving to shorten the sheet to such a degree that thelineal speed of the sheet 14 leaving the roll 10 was 47% of the speed ofthe sheet 11 arriving at the roll 10. The relationship between thespeeds of the sheet arriving at and leaving the creping roll is, ofcourse, an indication of the amount of crepe introduced into the sheet.The creped and uncreped sheets were then shredded by identical cuttingprocedures, so that the width of the shreds was identical.

Various samples of the creped and uncreped shreds were placed in thetest chamber referred to above, it having been determined that a readingof 6 pounds per square inch on the monometer corresponded to thefirmness of a commercial cigarette. The weight of uncreped, controltobacco which gave this standard reading on the monometer correspondedto a specific volume of the sample of 3.05 cubic centimeters per gram(cc./gm.). In contrast, the weight of creped tobacco which gave thisstandard reading corresponded to a specific volume of the sample of 3.78cc./ gm. Thus, it will be appreciated that the creped product had afilling power 24% greater than the uncreped product.

EXAMPLE II Cigarettes of all five sets were subjected to the compresasibility tester of the type described above. The plunger weighed 394grams. The results of the tests are tabulated below, the depth ofcompression reading being the average ten readings of each set:

Type Tobacco A set of commercial cigarettes was also subjected to thecompressibility tester, and the average reading was found to be 0.7 mm.

From the tabulation above, it will be seen that the filling power of thecreped tobacco falls somewhere be tween 15% and 35% greater than thecomparable uncreped tobacco. This confirms the finding of a 24% increase in filling power mentioned in Example I.

The invention has been shown and described in preferred form only, andby way of example, and many variations may be made in the inventionwhich will still be comprised within its spirit. It is understood,therefore, that the invention is not limited to any specific form orembodiment except insofar as such limitations are included in theappended claims.

What is claimed is:

1. A process for making a tobacco product for use in a smokable article,comprising the steps of forming a reconstituted tobacco sheet, applyingthe sheet while moist to a creping roll, creping the moist sheet bydoctoring the sheet from the roll, and cutting it into pieces suitablefor use as filler material in a smokable article.

2. A process as defined in claim 1 wherein formation of the sheetcomprises the steps of separating natural tobacco into fibrous materialand extract material, forming the fibrous material by papermakingtechniques into a paper-like sheet, and impregnating the sheet with saidextract material, and wherein said sheet is applied to the creping rollwhile still moist from impregnation of the extract.

References Cited UNITED STATES PATENTS 1,647,694 11/1927 Hawkins 131-143,230,958 1/1966 Dearsley l3114 X 3,298,378 1/1967 Stevens et al 131140FOREIGN PATENTS 1,146,420 3/1963 Germany.

MELVIN D. REIN, Primary Examiner.

U.S. Cl. X.R. 131--147, 14, 143

